A neuroanatomy research laboratory was made operative this year and has been used for studies of a) neuronal connections in the brain and b) localization of brain sites which are selectively involved in sleep and drug-induced sedation. The newly developed fiber tracing techniques based on tritiated amino acid autoradiography and horeseradish peroxidase (HRP) histochemistry have been used to demonstrate neural pathways arising from intralaminar and midline thalamus projecting to widespread areas of cerebral cortex and terminating in distinct laminar patterns. These data provide structural evidence for mechanisms of thalamocortical integration that have not previously been appreciated. In another form of autoradiography, labeled biologically active substances, tryptophan and diazepam, are systematically injected so that their final brain distributign can be mapped. The localization of the active uptake sites may lead to a better appreciation of the functional properties of tryptophan as a precursor to serotonin synthesis (which may be important in sleep mechanisms) and of diazepam as a pharmacologically potent tranquilizer, anticonvulsant and muscle relaxant.